I want to follow up on this comment for prospective buyers -- that Holosun is also widely seen as having extremely good quality for the money. Usually going cheap on an optic is not a good idea, but Holosun have been shaking things up with their offerings. E.g. the 407c/507c is a direct competitor to the Trijicon RMR which is considered the gold standard pistol optics (even uses the same mounting and recoil lug footprint). Trijicon actually filed a suit against Holosun, citing something about the brightness buttons (thus the "507C-X2" with different button layout), but I think it was really motivated by Holosun biting into their market share.